Electrical apparatus



Feb. 6, 1962 R. w. TWADDELL ETI'AL 3,

ELECTRICAL APPARATUS 3 Sheets-Sheet 1 Filed Jan. 6, 1958 IN V EN TORS E. GREGOIRE RUSS ELL W. TWADDELL STEPHEN Baku/MW ATTORNEYS Feb. 6, 1962 R. w. TWADDELL ETAL 3,020,449

ELECTRICAL APPARATUS Filed Jan. 6, 1958 3 Sheets-Sheet 2 INVENTORS I SE W. DDELL j 3 PH E. some 40 \/;Y

ATTORN EYS Feb. 6, 1962 R. w. TWADDELL ETAL 3,020,449

ELECTRICAL APPARATUS Filed Jan. 6, 1958 3 Sheets-Sheet 3 Q igh- INVENTORS RUSSELL W. TWADDELL STEPHEN E. GREGOIRE ATTO NEYS United States Patent 3,020,449 ELECTRICAL APPARATUS Iiusseli W. Twaddell and Stephen E. Gregoire, Sidney,

This invention relates to electrical apparatus, and more particularly to an electrically operated igniter unit designed for operation at high temperatures.

The invention has among its objects the provision of a novel electrically operated igniter unit designed for operation at high temperatures. r j

A further object of the invention resides in the provision of an electrically operated igniter unit having a novel arrangement and orientation of parts whereby it may operate without damage thereto for long periods under conditions in which it is subjected to marked vibration at elevated temperature.

Yet another object of the invention lies in the provision of an electrically operated igniter unithaving a novel chassis and housing structure.

Still a further object of the invention lies in the provision of an electrically operated igniter unit including a novel mechanism for mounting the unit on a support such as a jet, ram-jet, or other engine or the like which subjects the unit to marked vibration and elevated temperature.

The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressly understood, 7

however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a view in horizontal longitudinal, generally axial section through an illustrative embodiment of igniter unit made in accordance with the invention, the component parts of the igniter unit within the housing being shown generally in plan;

FIG. 2 is a view in end elevation of the igniter unit, the view being taken in a direction from left to right in FIG. 1;

FIG. 3 is a view in end elevation of the igniter unit, the view being taken in a direction from right to left in FIG. l;

PEG. 4 is a view in transverse section through the igniter unit at one end thereof, the section being taken along the line 44 of FIG. 1; and

5 is a fragmentary view in longitudinal section through a portion of the igniter unit in the vicinity of the trunniondike mounting means and bracket therefor at the left in FIG. "1, the section being taken generally along the line 5-5 of FIG. 1.

The igniter unit of the present invention may be used,

. for example, to start combustion in a jet or ram-jet engine. Because of the need for economy of space, as well as to reduce the length of electrical leads therefrom, the igniter unit is preferably mounted upon the casing of the engine which it is to serve. This subjects the igniter unit, however, to very severe operating conditions, since the housing of the engine when operating becomes highly heated and such housing vibrates markedly during operation of the engine. A successful igniter unit'for a use such as that above outlined must, therefore, be able to operate for long periods at elevated temperatures, and must be able to withstand marked vibrations while at elevated temperature. In addition, since the use of the engine requires that it be heated. from atmospheric ,or

ambient temperature to an elevated temperature when the 7 Cir engine is started, and'that it be cooled from the elevated temperature to atmospheric temperature when the engine is stopped, the igniter unit must be able to stand repeated marked changes in temperature and be able to absorbor compensate for dimensional changes in the parts, including the means mounting the various components in the igniter unit, and the means mounting the igniter unit on its support.

The igniter unit of the present invention, by way of illustration, includes a condenser assembly such as shown and claimed in application Serial No. 707,294, now Pat,- ent No. 2,942,167, and a rectifier mounting such as shown and claimed in application Serial No. 671,462. The components of the igniter unit may be connected in an igniter circuit such as that shown and claimed inthe application of London, Serial No. 665,558. v

Turning now to the drawings, the igniter unit asa whole is generally designated by the reference character 10. The unit is supported, for example, on the housing of a ram-jet engine (not shown) by brackets 11 and 12. Suchbrackets, except for the fuel pipes connected to opposite ends of the igniter unit and the electrical connections leading into and from the unit, constitute the sole mechanical connection between the igniter unit and its support. The brackets, as will be more readily apparent hereinafter, and the trunnion-like supporting means on the igniter unit engaged thereby, are designed to minimize the passage of heat from the engine housing to the igniter unit.

The igniter unit has an inner generally circular cylindrical housing 14, the ends of the housing being closed by flanged disc-like end closure members 15 and 1d welded thereto. The components of the igniter circuit are disposed within the inner housing, ina manner to be described, so as generally to be spaced from both the side wall and the endwalls thereof. Consequently, suchcircuit components receive heat from the engine only by conduction through the mounting brackets 11 and 12 to the end members 15 and 16 and thence to the supporting structure for the components, or by radiation from the engine housing to the housing of the igniter unit. To minimize the latter heating efiec't, there is employed an outer insulating housing made up of sheet metal and members 17 and19 and a central band-like member 20. A layer of heat insulating material 21, such as magnesia, is confined between the inner and outer housings, a shown.

The illustrative igniter unit 10 includes as components thereof a fiiter 26 having two similar elements 26 (FIG. 5), to isolate the unit from the current supply, thereby to eliminate radio interference, a transformer 25, a rectifier unit 27, a condenser unit 2-9,'and a' control gap 36. All of such components are contained within housing 14, and most of them are supported on a longitudinally extending framework which will be understood upon conbers 22 and 24 is composed of two flanged longitudinal members 13 and 13' which aremirror images of each other,'members 13 and 13 having the flanges thereof Each of frame CODBCtCdJEtS by welds 28, as shown. members 22 and 24 is secured to the respective end members 15 and 16 as by welding, two such welded joints being shown at 33 in FIG. 1. The circuit-forming componentsof the igniter are, with the exception of the control gapandfilter 26, all mounted upon frame members 22 and 24.. Thus, the transformer 25, havinga primary P and a secondary S, is mounted between the frame members, the core-supporting frame 53 of the transformer being bolted to a vertical plate member 72 extending between and secured as by being welded to frame members 13. The rectifier unit 27, which has opposite transverse end plate members 18 and 18', is disposed with such plate members spanning the distance between frame members 22 and 24 and secured thereto by studs 23. The condenser 29 is suspended between frame members 22 and 24 by a sheet metal band 64 which underlies the condenser unit and at opposite ends 65 thereof is secured to the frame members by screws 67, as shown in FIG. 4. The condenser is centered between the frame members by two inverted generally U-shaped bracket members 66 having their outer legs secured to the frame members, likewise as shown in FIG. 4. Filter units 26' are arranged side-by-side in a sub-enclosure, a portion of which is shown in FIG. 5. The sub-enclosure has a side wall 74, to which are sealed two end members, one of which is shown at 75. The subenclosure is supported by attachment of end member 75 to trunnion member 41, as by welding. The coil of each filter unit 26' is contained in can-like members 43, a condenser 76 for each unit being supported between the bottom of each member 43 and end member 75, and being electrically insulated from both member 43 and end member 75 by interposed layers of electrically insulating material such as Isomica.

The control gap 30 is mounted on the housing end member 15, as shown in FIGS. 1 and 4. A generally U-shaped sheet metal bracket 69 has the base 70 thereof attached as by welding at 71 to member 15. Preferably, as shown, the vertical and horizontal edges of the base are flanged to the right in FIG. 1, so that only the free edges of such flanges contact end member 15. The metallic casing of the control gap 30 is secured, as by being welded thereto, to the outer free ends of arms 72 of bracket 69. The resulting construction cradles the control gap between the opposite resilient arms 72 of the bracket 69, so as to protect it from vibration. The frame members 22 and 24 are assembled as shown, the ends of the frame members 22, 24 are then welded to end closure members 15 and 16 at zones 33, and the components of the igniter circuit are mounted thereon. Following this, the thus formed assembly is telescoped into inner housing member 14 in a direction from right to left in FIG. 1. The end closure members may then be welded to housing member 14. For convenience of assembly the opening through the right hand end of housing member 14 (FIG. 1) and end member 15 are made of a somewhat larger diameter than the opening at the left hand end of member 14 and end member 16.

The igniter unit shown is adapted to be cooled by circulating the fuel for the engine therethrough prior to its being fed to the engine. By so doing, the temperature of the components, which might, for example, otherwise rise to 800 to 900 F. during an extended run of the engine, will be maintained, at, for example, on the order of 550 F. The housing is provided at opposite ends thereof with inlet and exhaust pipes to permit such flow through the unit. Such pipes, designated 31 and 32, are shown in FIG. 1 attached to end members 15 and 16, respectively.

The means whereby the igniter unit is mounted on a support such as an engine housing is shown more particularly in FIGS. 2, 3, and 5. Such means takes the form of two oppositely extending hollow trunnion-like members 34 and 41 secured to the end members 15 and 16, respectively, and offset somewhat in opposite directions from the longitudinal axis of the unit. Not only do such trunnion-like members support the igniter unit, but they also conveniently serve as portions of housings of separable connectors by means of which the igniter unit is supplied with operating current and is connected to the igniter device, such as an igniter plug, in the engine.

The construction of the two igniter unit-mounting means is generally similar, so that only the mounting means shown in the left in FIG. 1 will be described in detail. The parts of the mounting means shown at the right in FIG. 1 are designated by the same reference characters with an added prime. As shown in FIGS. 2 and 5, the trunnion-like means 41 is in the form of a tube having a flange 77 welded to end member 16. Intermediate its length member 41 is provided with a peripherally extending flange 5'4- which has a central circular cylindrical zone bounded by oppositely inclined end surfaces so that the flange is of truncated V-section at its periphery. The flange is provided centrally of its axial extent with a relatively deep peripherally extending slot or groove 55.

The bracket 11 has a base 40, a flange portion 39, and a bottom trunnion-receiving portion 54) secured to the flange. The cap 42 for portion 50 is secured to the main portion of the bracket by studs 38. The peripherally extending seats in portions 42 and 50 of the bracket each has a shape that is complementary to flange 54, having a central circular cylindrical peripheral zone 51 and two, oppositely inclined frusto-conical end zones 52, 52'. The trunnion-like members 34 and 41 are mounted in the respective brackets 11 and 12, the caps 42 and 42 of which are tightened onto the flanges thereof. The peripheral groove 55 reduces the area of surface contact between the brackets and the trunnion-like members, thereby to reduce the rate of heat transmission through the brackets and into the trunnion-like members.

Trunnion-like member 41 also serves as a portion of the housing of a separable electrical connector through which electric power is supplied to the igniter unit through wires 45 which are shown somewhat in FIG. 5 leading to the igniter through member 41. As shown in FIG. 5, axially disposed within member 41 there is an insulator 79 supporting contacts to which are connected to the wires 45 leading into the igniter unit, as shown.

The other part of the separable connector, now shown, has an elongated connector member bearing two contacts, such connector member being adapted to be inserted axially into the outer end of member 41 so that its contacts may make contact with the contacts on insulator '79. The housing of such other connector part is adapted to be secured to member 41 by having a nut on such connector part screwed on to threaded portion 44 of member 41. The other trunnion-likemember 34 has a threaded portion 36 on the outer end thereof, whereby an outer part of another separable connector, not shown, may be secured to member 34. Such other separable connector, which may be constructed somewhat similarly to the connector described in connection with member 41, is adapted to connect a single delivery lead wire from the igniter unit to an igniter device or plug.

Although only one embodiment of the invention has been illustrated in the accompanying drawings and described in the foregoing specification, it is to be expressly understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. An electrically operated igniter adapted to operate at elevated temperatures, comprising an elongated rigid casing, closure members secured to the ends of the casing, spaced wide parallel longitudinally extending frame members extending chordally of the casing and attached to the end closure members and spaced from the sidewall of the casing, rigid housings of units which contain at least some of the elements of the igniter circuit located between and suspended from the frame members, oppositely, generally axially outward propjecting trunnion-like supporting members for the casing attached to the respective end closure members, and igniter unit supporting brackets adapted to be clampingly secured to the supporting members. i

2. An electrically operated igniter adapted to operate at elevated temperatures, comprising an elongated rigid casing, closure members secured to the ends of the casing, spaced parallel longitudinally extending frame members attached to the end closure members and spaced from the sidewalls of the casing, and rigid housings of units which contain at least some of the elements of the igniter circuit located within the casing, at least one unit lying between and secured to said frame members at a location spaced from the end closure members, and at least one other unit being narrower than the distance between opposite frame members and being positioned generally symmetrically between said members, and means for securing said other unit com-prising generally U-shaped brackets interposed between the sides of said other unit and the respective frame member, the opposite legs of each U-shaped bracket being secured to the respective frame member and side of the unit.

3. An electrically operated igniter adapted to operate at elevated temperatures, comprising a rigid casing, closure members secured to the opposite ends of the casing, said casing containing at least some of the elements of the igniter circuit, oppositely outwardly projecting trunnion-like supporting members for the casing attached to the respective end closure members, supporting brackets for the trunnion-like members, each of the trunnion-like members having a circumferential flange, and each of the supporting brackets having a circumferentially extending socket receiving its respective flange.

4. An igniter as defined in claim 3, wherein the flanges have an angular external configuration, the sockets have a configuration complementary to the configuration of the flanges, and the flanges are deeply. peripherally grooved intermediate their axial lengths. I

5. An electrically operated igniter adapted to operate at elevated temperatures, comprising an elongated rigid casing, closure members secured to the ends of the casing, spaced wide parallel longitudinally extending frame members extending chordally of the casing and attached to the end closure members and spaced from the sidewall of the casing, rigid housings of units which contain at least some of the elements of the igniter circuit located between and suspended from the frame members, an electrical unit lying between and secured to said frame members at a location spaced from the end closure members, the unit being narrower than the distance between opposite frame members and being positioned generally symmetrically between said members, and generally U- shaped brackets interposed between the sides of the unit and the respective frame member, the opposite legs of each U-shaped bracket being secured to the respective frame member and side of the unit.

6. An electrically operated igniter adapted to operate at elevated temperatures, comprising an elongated rigid casing, closure members secured to the ends of the casing, spaced wide parallel longitudinally extending frame members extending chordally of the casing and attached to the end closure members and spaced from the sidewall of the casing, rigid housings of units which contain at least some of the elements of the igniter circuit located between and suspended from the frame members, an electrical unit lying between and secured to said frame mem-,

bers at a location spaced from the end closure members, said unit being suspended from one end closure member by a generally U-shaped bracket having the bight thereof secured to said end closure member, the unit being located between and secured to the outer ends of the opposite legs of the bracket.

References Cited in the tile of this patent 

